Image projecting apparatus

Abstract: In an image projecting apparatus such as a microfilm reader and a microfilm reader printer, without causing no distortion and blur in a projected image on a screen surface, the inclination angle of the screen can be changed for the user to see the screen surface with ease such that the screen surface becomes rectangular to the user's line of sight and the external light reflected by the screen surface is prevented from entering the user's eyes.

Description: BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to an image projecting apparatus such as a microfilm reader and a microfilm reader printer. Related Background Art In a conventional film reader or reader printer, generally, a screen of a reader section is secured to its apparatus body in an upright state. Therefore, the angle of the screen cannot be changed. Then, when observing an image projected on the screen, depending on the height of the apparatus, the height of the chair or users' sitting heights, some users cannot see the screen surface well and need to see it upwardly (angle of elevation) or downwardly (angle of depression) as their line of sight does not become orthogonal thereto. Also, even though the external light such as fluorescent light and outdoor daylight reflected by the screen surface enters users' eyes and the users cannot see the projected image on the screen surface well, they cannot prevent its condition by changing the angle of the screen. In JP-A-58161480 a television receiver of the projective type is disclosed having a television projection tube, and a first and a second mirror for projecting television pictures on a screen. The second mirror and the screen are rigidly fixed together by a swivel arm. The swivel arm is pivotly arranged around a central part of the second mirror, so that the screen and the second mirror rotate in common. By rotating the screen the center of the displayed image is shifted. Such shift of the displayed image results in an image distortion and the displayed image is running out-of-focus. From US 5,047,800 an image projecting apparatus is known having a fixedly arranged screen and mirrors for projecting an image onto the screen. This apparatus further comprises a printing section for printing an image. In the optical path between a light source for illuminating a microfilm and said screen an image rotating prism for rotating the direction of the image to be projected and an optical element for shifting the optical axis are arranged. These optical elements allow to correct the position of an image to be recorded. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an image projecting apparatus which enables a user to see the surface of a screen with ease. The object is solved by an image projecting apparatus according to claim 1. Advantageous embodiments are defined in the subclaims. At least one reflection mirror is provided in a projection optical system for projecting the image of the image carrying member on the screen. When changing the inclination angle of the screen, both the screen and the reflection mirror are rotated correspondingly such that the optical axis of the projection optical axis directed to the screen surface is constantly kept approximately orthogonal to the screen surface. In another preferred embodiment, both the screen and the image carrying member are correspondingly rotated when changing the inclination angle of the screen. According to the present invention, since the screen is rotatable, it is possible to adjust the inclination angle of the screen for the user to see the screen surface well such that the screen surface becomes orthogonal to the user's line of sight or the external light reflected by the screen surface is prevented from entering the user's eyes. Also, since both the screen and the at least one reflection mirror are correspondingly rotated at the time of changing the inclination angle of the screen such that the optical axis of the projection optical system directed to the screen surface is constantly kept approximately orthogonal to the screen surface, no distortion or blur occurs in the projected image on the screen surface even though the inclination angle of the screen surface is changed so as to be suitable for the user's line of sight or to prevent the external light reflected by the screen surface from entering the user's eyes. Further, both the inclination angles of the screen surface and the image carrying member are changeable, so that no blur occurs in the projected image on the screen surface even though the inclination angle of the screen is changed so as to be suitable for the user's line of sight or to prevent the external light from entering the user's eyes. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram of a microfilm reader printer of a first embodiment according to the present invention; Fig. 2A is a side view of an interlocking mechanism of the screen and the first mirror for the reader of the first embodiment; Fig. 2B is a plan view of Fig. 12A; Fig. 3A is a schematic view illustrating an interlocking relationship of a screen and a first mirror of a second embodiment according to the present invention; Fig. 3B is a schematic view of the interlocking mechanism of the second embodiment; Fig. 4 is a schematic view illustrating an interlocking relationship of a screen and a first mirror of a third embodiment according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Fig. 1 is a schematic diagram illustrating a microfilm reader printer of a first embodiment according to the present invention. The microfilm reader printer has a casing 101 and a transmission-type screen 102 (rear type) for the reader disposed on the front side of the casing 102. A illuminating unit section 103 is constituted of a light source lamp 103a, a spherical reflecting mirror 103b, a condenser lens 103c or the like. A microfilm carrier 104 is provided over the illuminating unit section 103 and is a microfiche carrier but may be a roll film drive mechanism. The carrier 104 has two upper and lower platen glasses 104a and 104b. A microfiche film F is sandwitched between the platen glasses 104a and 104b. A desired image frame of the microfiche film F is disposed at an illuminating position S by shifting the carrier 104 lengthwise and/or widthwise. In the reader mode, light from the lamp 103a illuminates the image frame disposed at the illuminating position S. The light transmitting the image frame reaches the rear surface of the screen 102 via a projection optical system (for reader) formed of a projection lens 105, a first mirror 106 for the reader, a second mirror 107 for the reader and the screen 102 to project a magnified image of the image frame thereon. The projected magnified image can be observed outside the screen 102. First and second movable scan mirrors 108 and 109 for a printer are held by a holding member 110 such that light from the lamp 103a is reflected orthogonally by both the first and second mirrors 108 and 109. The holding member 110 is moved by a drive mechanism (not illustrated) in the left and right directions a and b reciprocatively. A numeral number 111 is a printer section having, e.g., a transfer type electrophotographic processing mechanism. In Fig. 1, only a rotatable sensitive drum 111a and a slit exposure plate 111b of the electrophotographic processing mechanism are illustrated and a primary charger, a developing unit, transferring means, fixing means, paper feeding means thereof are omitted. At the time of the reader mode, the holding member 110 is retained in a wait and stop condition at a forward motion starting position as a home position as indicated by a solid line on the right. In this condition, the first movable scan mirror 108 is positioned outside the light pass from the projection lens 105 to the first mirror 106 for the render and will not be a hindrance to the reader light path. In the printer mode, the holding member 110, i.e., the first and second movable scan mirrors 108, 109 are driven forwardly (back scan) in the left direction a from the home position, during which the first movable scan mirror 108 intersects the reader light path from the projection lens 105 to the first mirror 106 for the reader. After the first and second movable scan mirrors 108, 109 reach forward end points 108', 109' (exposure start points), the drive of the holding member 110, i.e., the first and second movable scan mirrors 108, 109 is switched to the backward drive. During the backward drive, the light from the projection lens 105 is scanned by the first movable scan mirror 108. The scanned light is reflected by the second movable scan mirror 109 to pass a slit formed in the slit exposure plate 111b to reach the rotatable sensitive drum 111a on a surface of which then an image is formed. That is, the image information of the image frame of the microfiche film F on the lighting position is exposed on the surface of the sensitive drum 111a through the slit. Thus, the printing process is started. At the time of printing, the sensitive drum llla is rotated clockwise as indicated by an arrow at a constant peripheral speed while the holding member 110, i.e., the first and second movable scan mirrors 108, 109 are shifted at a half speed of the peripheral speed of the sensitive drum 111a. After the exposure, the holding member 110 is returned to the initial home position as indicated by the solid line, wherein the first movable scan mirror 108 is out of the reader light pass. In this embodiment, the screen 102 can be freely inclined upwardly or downwardly as indicated by the two-dot-chain lines in Fig. 1 from the upright condition by a mechanism (see Fig. 2A) to be described later. Then, the inclination angle of the screen can be adjusted such that the user's line of sight becomes perpendicular to the screen surface for easy observation or the external light reflected by the screen surface is prevented from entering the user's eyes. At this time, the second mirror 107 for the reader is moved or rotated to, e.g., positions 107, 107', 107" in accordance with the rotating movement of the screen 102 such that the screen surface is always kept approximately orthogonal to an optical axis 0, 0' or 0" of the projection optical system directed to the screen surface in spite of positions 102, 102', 102" of the screen 102. Fig. 2A is a side view of an interlocking mechanism of the screen 102 and the second mirror 107 in this embodiment and Fig. 2B is a plan view thereof. Axle pins 121 are provided on both lateral ends of the second mirror 107 so as to project therefrom. The axle pins 121 are received and supported rotatably by bearing plates 122 secured to stationary members provided on the apparatus body. Therefore, the second mirror 107 is rotatable around the axle pins 121 between the bearing plates 122. The axle pins 121 are provided with a horizontal line A as the center, the horizontal line A passing the intersecting point of the optical axis and the reflection surface of the second mirror 107 and being within the reflection surface of the mirror 107. A pair of screen levers 123 are formed on lateral sides of the screen 102 integrally with the screen 102 and are parallel to each other. The levers 123 are extended toward the inside of the apparatus. Ends of the levers 123 on the opposite side to the side of the screen 102 are formed with holes in which the respective axle pins 121 are fitted, whereby the levers 123 are moved freely upwardly and downwardly around the axle pins 121. That is, the screen 102 is connected via the levers 123 to the axle pins 121 so as to rotate upwardly or downwardly around the axle pins 121. A mirror gear 124 is provided concentrically and integrally on one of the axle pins 121 and integrated to the second mirror 107. A screen lever gear 125 is concentrically and rotatably fitted on the axle pins 121 to face the mirror gear 124 and integrally formed with the inside surface of the screen lever 123. Double gears 126 and 127 are concentric with each other and received and supported by a bearing plate 128 secured to a stationary member of the apparatus body. The gear 126 is engaged with the screen lever gear 125 while the gear 127 is engaged with the mirror gear 124. Friction members 129 are provided in gaps between the side ends of the double gears 126, 127 and the bearing plate 128 so as to impart resistance to the rotation of the double gears 126, 127. The gear ratio of the screen lever gear 125 to the gear 126 is as follows: gear 125 : gear 126 = 1 : 1 The gear ratio of the mirror gear 124 to the gear 127 is as follows: gear 124 : gear 127 = 2 : 1 When the screen 102 is rotated upwardly or downwardly around the axle pins 121 against the friction resistance of the friction members 129 to the position 102, 102' or 102" by operating a knob (not illustrated) formed integrally with the screen 102 or the screen lever 123, the second mirror 107 is correspondingly rotated around the axle pins 121 via the screen lever gear 125, the one gear 126 of the double gears, the other gear 127, the mirror gear 124, the axle pin 121 to the position 107, 107' or 107". Even though the user releases his hand from the knob after the screen 102 is rotated upwardly or downwardly to a certain position, the friction resistance of the friction members 129 surpasses downward rotation moment of the levers 123 due to the weight of the screen 102 thereby to prevent the gears from rotating spontaneously. When the screen 102 needs to be inclined further upwardly from the present position, the screen 102 is rotated around the axle pins 121 clockwise in Fig. 2A by the knob, whereby the screen lever gear 125 is integrally rotated around the axle pin 121 clockwise. At this time, when the displacement angle is assumed to be  and the gear 125 is rotated clockwise at the angle , the one gear 126 of the double gears whose gear ratio with respect to the gear 125 is 1:1 and the other concentric gear 127 are rotated together at the angle . Then, the mirror gear 124 whose gear ratio with respect to the gear 127 is 2:1 and the second mirror 107 formed integrally with the gear 124 are rotated around the axle pins 121 clockwise at the angle /2 correspondingly. Also, when the screen 102 needs to be inclined further downwardly from the present position, the screen 102 is rotated around the axle pins 121 counterclockwise in Fig. 2A by the knob. At this time, the second mirror 107 is rotated around the axle pins 121 counterclockwise at the angle /2 by means of the opposite operation to the above. Thus, when the displacement angle ratio of the screen 102 to the second mirror 107 is 2:1, from the optical rule, the optical axis 0, 0' or 0" of the projection optical system directed from the second mirror 107 to the screen 102 is always orthogonal to the screen surface in spite of the position 102, 102' or 102" of the screen 102 (see Fig. 1). As a result, even though the inclination angle of the screen 102 is changed so as to be suitable for the user's line of sight or to prevent the external light reflected by the screen surface from entering the user's eyes, no distortion or blur occurs in the projected image on the screen surface. Also, as the second mirror 107 is moved together with the screen 102 correspondingly, no influence is exerted on the printer system and there is no need to return the mirror or the like to the initial position. Figs. 13A and 13B illustrate a second embodiment according to the present invention. In this embodiment, the first mirror 106 of the projection optical system for the reader is moved to, e.g., a position 106, 106' or 106" in accordance with the change of the inclination angle of the screen 102, i.e., the position 102, 102' or 102" of the screen 102. The second mirror 107 is secured stationarily at a predetermined angle. Fig. 3B illustrates an interlocking mechanism of the screen 102 and the first mirror 106. A pair of cam hole plates 131 are provided fixedly on the apparatus body on the lateral sides of the screen 102. The cam hole plates 131 are formed with respective arcuate guide cam holes 132 symmetrically with the horizontal line A within the reflection surface of the second mirror 107 as the center. Guide pins 33 and 34 are formed on the lateral sides integrally with the screen 102 so as to project outwardly. The guide pins 133 and 134 are fitted in the respective arcuate guide cam holes 132 of the cam hole plates 131. The screen 102 is rotatable around the horizontal line A within the reflection surface of the second mirror 107 owing to the arcuate guide cam holes 132 and the guide pins 133 and 134. The screen 102 is inclined upwardly or downwardly to be in the position 102, 102' or 102" by the operation of the knob (not illustrated) formed integrally with the screen 102 and retained in the position 102, 102' or 102" securely as the friction members (not illustrated) prevent downward rotation of the screen 102 caused by its own weight. The first mirror 106 is freely rotatable around a horizontal line A within the reflection surface thereof. A numeral number 135 is a central axis of its rotation and provided with the horizontal line A as the center, the horizontal line A passing the intersecting point of the reflection surface of the first mirror 106 and the optical axis and being within the reflection surface of the mirror 106. The mechanisms provided on both the lateral sides of the screen 102 for rotating the screen 102 and the first mirror 106 are the same, so the mechanism on the one side thereof will be described hereinafter. A spring 136 urges the mirror 106 constantly counterclockwise around the axis 135. A lever 137 is rotatable around a pivot 138 and urged constantly counterclockwise by a spring 139. One arm 137a of the lever 137 is in contact with the upper guide pin 133 of the screen 102 while the other arm 137b is in contact With the first mirror 106. When the screen 102 is inclined further upwardly from the present condition by the knob, the guide pins 133, 134 are pushed up in the guide cam hole 132, which causes the arm 137a of the lever 137 is pushed up by the guide pin 133. Thereby, the lever 137 is rotated around the pivot 138 clockwise against the force of the spring 139. At this time, the other arm 137b of the lever 137 is rotated downwardly to cause the first mirror 106 to rotate around the axis 135 counterclockwise by the force of the spring 136. That is, the first mirror 106 is rotated counterclockwise in accordance with the upward movement of the screen 102, so that the optical axis 0, 0' or 0" of the projection optical axis directed from the second mirror 107 to the surface of the screen 102 is constantly kept orthogonal to the surface of the screen 102 in spite of the change of the inclination angle of the screen 102 due to the upward inclination of the screen 102. When the screen 102 is inclined further downwardly from the present position by the knob, the guide pins 133, 134 are lowered in the guide cam hole 132. At this time, as the arm 137a of the lever 137 presses the guide pin 133 constantly by means of the spring 139, the other arm 137a of the lever 137 is rotated downwardly. Thereby, the lever 137 is rotated around the pivot 138 counterclockwise to cause the arm 137b of the lever 137 to be raised. As a result, the mirror 106 is rotated clockwise around the axis 135 against the force of the spring 136. That is, the first mirror 106 is rotated clockwise in accordance with the upward movement of the screen 102, so the optical axis 0, 0' or 0" of the projection optical system directed from the second mirror 107 to the surface of the screen 102 is constantly kept orthogonal to the surface of the screen 102 in spite of the change of the inclination angle of the surface of the screen 102 due to the upward movement thereof. Therefore, even though the inclination angle of the screen 102 is changed so as to be suitable for the user's line of sight or to prevent the external light reflected by the screen surface from entering the user's eyes, no distortion or blur occurs in the projected image of the screen surface. Because the mirror of the projection optical system to be moved together with the screen 102 is the first mirror 106 close to the screen 102 in this embodiment, it is advantageous that its interlocking mechanism is compacter than that in the first embodiment. Fig. 4 illustrates a third embodiment of the present invention. In this embodiment, in order to keep the optical axis 0, 0' or 0" of the projection optical system directed from the second mirror 107 to the surface of the screen 102 constantly orthogonal to the surface of the screen 102 in spite of the change of the inclination angle of the screen 102, i.e., the position 102, 102' or 102" of the screen 102, both the first mirror 106 and the second mirror 107 are moved to, e.g., the position 106, 106' or 106" and the position 107, 107' or 107" respectively in accordance with the change of the inclination angle of the screen 102. In this embodiment, the screen 102 is rotatable around the central horizontal line B to be in the position 102, 102' or 102". The first mirror 106 is rotatable around the horizontal line A within the reflection surface of the mirror 106 to be in the position 106, 106' or 106" in a similar manner to the second embodiment. Also, the second mirror 107 is rotatable around the horizontal line B of the screen 102 to be in the position 107, 107' or 107" in a manner opposite to the relationship between the screen 102 and the second mirror 107 in the first embodiment. The interlocking mechanism of the screen 102 and the first and second mirrors 106, 107 is omitted in Fig. 14, but can be structured by combining the interlocking mechanisms in the first and second embodiments. Even though the inclination angle of the screen 102 is changed so as to be suitable for the user's line of sight or to prevent the external light reflected by the screen surface from entering the user's eyes also in this embodiment, no distortion or blur occurs in the projected image of the screen surface also in this embodiment. In this embodiment, the screen 102 is moved around the horizontal line B, there is no need to change the visual point. Also, there is no need to provide an extra space for the screen 102 to move upwardly or downwardly and then the apparatus can be formed compacter. In the first to third embodiments, after the screen 102 is inclined by the user, the second mirror 107, the first mirror 106 or both the first and second mirrors 106, 107 are inclined. However, conversely, the mirror may be first inclined and then, the screen is inclined in accordance with the movement of the mirror. Also, after making electrical detecting means detect the inclination of the screen, the mirror may be inclined by driving electrical drive means such as a monitor based on the detected data. Further, by inputting the inclination angle of the screen from an operating section, the screen and the mirror may be moved correspondingly by means of electrical drive means. In the image projecting apparatus according to the present invention, as described above, the screen is inclinable and then, the inclination angle of the screen surface can be adjusted for the user to see the projected image of the screen surface easily such that the user's line of sight is orthogonal to the projected image or the external light reflected by the screen surface is prevented from entering the user's eyes. In this case, in spite of the change of the inclination angle of the screen, the screen and the mirror in the projection optical system are moved correspondingly such that the optical axis of the projection optical system directed to the screen surface is constantly kept approximately orthogonal to the screen surface, so that no distortion or blur occurs in the projected image on the screen surface.

Claims: An image projecting apparatus comprising: illuminating means (103) disposed in an apparatus body (101) for illuminating an image carrying member (F); a screen (102) disposed in said apparatus body (101) such that the inclination angle of said screen (102) with respect to said apparatus body can be adjusted; an optical system for projecting an image of said image carrying member (F) illuminated by said illuminating means (103) on said screen (102), said optical system including at least one mirror (106, 107) with an adjustable inclination angle with respect to said apparatus body; and means (121-129; 131-139) for changing the inclination angle of said screen (102) and said mirror (106, 107), said inclining means changing the inclination angle of said mirror (106, 107) in accordance with the inclination angle of said screen (102), characterized in that said inclining means are arranged to change the inclination angles of said screen (102) and said mirror (106, 107) by different angles of inclination with respect to each other so that said screen (102) is kept substantially orthogonal to the axis (0) of projection of said optical system on said screen. An image projecting apparatus according to claim 1, wherein said inclining means includes connecting means (123) for rotating said screen (102) and said mirror (106, 107) in coordination with each other. An image projecting apparatus according to claim 1 or 2, wherein said screen (102) is manually rotatable. An image projecting apparatus according to claim 3, wherein said screen (102) and said mirror (106, 107) are rotated about a same rotation axis. An image projecting apparatus according to claim 4, wherein said connecting means (123, 137) rotates said mirror by an angle when said screen (102) is rotated by an angle. An image projecting apparatus according to claims 1 to 5, wherein said optical system includes a plurality of mirrors (106, 107) whose inclination angles are adjustable. An image projecting apparatus according to any one of the preceding claims, wherein said screen (102) and said mirror (106, 107) are rotated in coordination so that an image of the film is projected substantially onto the same position on said screen. An image projecting apparatus as defined in any one of the claims 2 to 7, further comprising drive means for rotating said screen (102) and said mirror (106, 107). An apparatus as defined in any one of the preceding claims, further comprising detecting means for detecting the inclination angle of said screen and drive means for rotating said mirror in accordance with said detected inclination angle of said screen. An apparatus as defined in any one of the preceding claims, wherein said screen (102) is a transmission-type diffusion plate. An apparatus as defined in any one of the preceding claims, further comprising printing means (111) for printing the image of said image carrying member (F) and selecting means (110) for selectively projecting the image of said image carrying member on said screen (102) or said printing means (111). An apparatus as defined in any one of the preceding claims, wherein said image carrying member is a microfilm (F).

Inventors: ONUKI KAZUHIKO, SUGIYAMA KAZUHIDE, YAMAGUCHI YUKUO, ONUKI, KAZUHIKO, SUGIYAMA,KAZUHIDE, YAMAGUCHI, YUKUO, ONUKI, KAZUHIKO, C/O CANON KABUSHIKI KAISHA, SUGIYAMA,KAZUHIDE, C/O CANON KABUSHIKI KAISHA, YAMAGUCHI, YUKUO, C/O CANON KABUSHIKI KAISHA
Applicants: CANON KK, CANON KABUSHIKI KAISHA
Application year: 1994
Main classification: G03B21
IPC codes: G03B21